Mobile drilling rig having adjustable boom

ABSTRACT

The drilling rig comprises a boom, one end of which is arranged to be pivotally attached to the vehicle while the other end supports a drilling-head carrier arm tiltably mounted thereon. The carrier arm is also rotatably mounted about an axis normal to the axis of tilting. The boom is arranged to be pivoted in a vertical plane by at least one hydraulic piston-and-cylinder unit attached to a vehicle and connected to the hydraulic system. The carrier arm is tiltable over an arc of 180* by an endless drive transmission extending from one end of the boom to the other. In one embodiment the transmission includes a drive wheel located at or close to one end of the boom. The drilling rig may be attached to a buck-digger vehicle having a hydraulic actuating system for providing the necessary hydraulic source.

Jan. 23, 1973 United States Patent 1 Hunt [ MOBILE DRILLING RIG HAVINGADJUSTABLE BOOM Primary ExaminerErnest R. Purser Attorney-Robert R.Finch and Richard F. Bojanowski Inventor: William Allen Hunt, Tynemouth,

England [57] ABSTRACT The drilling rig comprises a boom, one end ofwhich is [73] Assignee: Envirotech Corporation, Salt Lake City, Utaharranged to be pivotally attached to the vehicle while the other endsupports a drilling-head carrier arm tiltably mounted thereon. Thecarrier arm is also [22] Filed: Jan. I1, 1971 [21] Appl.No.: 105,260

rotatably mounted about an axis normal to the axis of tilting. The boomis arranged to be pivoted in a vertical plane by at least one hydraulicpiston-and-cylinder unit attached to a vehicle and connected to thehydraulic system. The carrier arm is tiltable over an 62 6 40 4 NH 719MJ "M 3 7 21 ME/ 3 m 7 .7 1 n mmh "c r "Na Hue a L 0 d sum. UIF ll] 218555 [ll arc of 180 by an endless drive transmission extending from oneend of the boom to the other. In one em- Reierences Cited bodiment thetransmission includes a drive wheel UNITED STATES PATENTS FOREIGNPATENTS OR APPLlCATlONS located at or close to one end of the boom. The

drilling rig may be attached to a buck-digger vehicle having a hydraulicactuating system for providing the necessary hydraulic source.

l-lendrickson et 925,281 3/1955Germany................................173/43 19 Claims, 6 DrawingFigures PATENTEDJAH 23 1973 SHEET 2 BF 5 PATENTEDJM123 ma SHEET 3 UF 5mam R PATENTEUJAN23 ma SHEET 5 BF 5 FIGS MOBILE DRILLING RIG HAVINGADJUSTABLE BOOM BACKGROUND OF THE INVENTION This invention relates todrilling rigs attachable to bucket-digger vehicles, including thoseadapted for side-tipping, equipped with a hydraulical actuating system.

OBJECTS OF INVENTION It is a primary object of this invention to providea drilling rig which is adapted for attachment to existing digging orloading equipment. Another object of this invention is to provide adrilling rig adaptable for connection and use to hydraulic activatingsystems carried by existing equipment.

Still another object of this invention is to provide a drilling rigadapted for side tipping and equipped with a hydraulic actuating system.

SUMMARY OF THE INVENTION The invention aims at providing a drilling rigso designed that it can be attached to the front or rear of a vehicle ofthe type referred to in such a way that the latter with the attachmentmounted thereon may still be used for its basic or main purpose, that isto say digging and loading. Accordingly, for one aspect, the inventionconsists in a drilling rig attachable to a bucket-digger vehicleequipped with a hydraulic actuating system, wherein the drilling rigcomprises a boom one end of which is arranged to be pivotally attachedto the vehicle while the other end supports a drilling-head carrier armtiltably mounted thereon and rotatable about an axis normal to the axisof tilting, wherein the boom is arranged to be pivoted in a verticalplane by at least one hydraulic piston-and-cylinder unit attachable tothe vehicle and connectable to the hydraulic system, and wherein thecarrier am is arranged to be tilted over an arc of substantially 180 byan endless drive transmission extending substantially from the one endto the other end of the boom.

From another aspect the invention consists in a drilling rig attachableto a bucket-digger vehicle equipped with a hydraulic actuating systemwherein, the drilling rig comprises a boom one end of which is arrangedto be pivotally attached to the vehicle while the other end supports adrilling-head carrier arm tiltably mounted thereon and rotatable aboutan axis normal to the axis of tilting wherein the boom is arranged to bepivoted in'a vertical plane by at least one hydraulicpiston-and-cylinder unit attachable to the vehicle and connectable tothe hydraulic system, wherein the carrier arm is arranged to be tiltedover an arc of substantially 180 by an endless-drive transmissionextending substantially from one end to the other end of the boom, andwherein the transmission includes a drive wheel located at or close tothe one end of the boom.

Preferably, the boom of a drilling rig attachment according to theinvention is pivoted by means of two hydraulic piston-and-cylinderunits, one of which may be permanently attached to the vehicle while theother one requires to be detached therefrom when the drilling operationfor which the attachment is used has been completed and the attachmentis stowed away.

In order to make the invention more thoroughly understood and to explainsome additional features thereof, two embodiments thereof will now bedescribed in more detail with reference to the accompanying diagrammaticdrawings.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a side view of a bucket-diggerincluding an attachment according to the invention.

FIG. 2 is an end view of part of the digger and the attachment.

FIG. 3 is a side view, on an enlarged scale of a modified embodiment ofthe attachment.

FIG. 4 is an end view of the attachment illustrated in FIG. 3.

FIG. 5 is a side view of a boom-mounting bracket of the attachment andmeans for rotating the boom in a horizontal plane.

FIG. 6 is a plan view of the rotating means illustrated in FIG. 5.

DESCRIPTION OF PREFERRED EMBODIMENT A drilling attachment according tothe invention is mounted on the frame of a bucket-digger vehiclegenerally denoted by the reference character X and being equipped with ahydraulic actuating system. It comprises a boom 2 the lower end of whichis universally mounted to allow motion in horizontal and verticalplanes. For this purpose, it is held in a bracket 4 mounted in a bearing6 attached to the vehicle frame. The boom 2 in the embodimentillustrated is pivotable in bothplanes by two hydraulicpiston-and-cylinder units 8 and 10 and held by them in any selected position within its pivotal range. The piston-and-cylinder units 8 and 10are attached to the vehicle frame and connected to the hydraulic systembut one of the units, the unit 10 in the embodiment illustrated, is soconnected to the vehicle that it can be detached therefrom to permit thevehicle to operate as a digger and tipper. The operation of the units 8and 10 is controlled by suitable hydraulic valves not shown which may behand-operated. Since, as indicated, the piston-andcylinder units areconnected or connectable to the hydraulic system of the vehicle noseparate pump and reservoir are required for delivering the hydraulicpressure fluid to and emptying it from the cylinders, the pump andreservoir of the vehicle system being used for this purpose.

The other, upper, end of the boom 2 supports a drilling-head carrier arm12 by means of a support 14 and a block 16. The carrier arm 12 includingthe support 14 fixed thereto are rotatably mounted in the block 16 insuch a fashion that unless locked they can be rotated over 360 in andrelative to the block 16, in a plane parallel to the upper end face ofthe block. The support 14 is lockable in the block 16 in any desiredposition by tightening clamps 18. The block 16 is arranged to beswivelled in a vertical plane over an arc of substantially and to beheld in any desired position within this arc by an endless drivetransmission comprising a chain-20 trained over two sprockets 22 and 24of which the latter is rigidly attached to the block 16. The sprocket 22is located at the lower end of the boom 2 which is pivotally attached tothe vehicle frame. This sprocket is the drive sprocket of thetransmission and is arranged to be turned in the embodiment illustratedin FIGS. 1 and 2 by a worm and worm-wheel drive 23 which maybe hand orpower operated. The chain and sprocket transmission may be replaced byan endless V-belt and two pulleys at least the driving one of which maycomprise two discs hydraulically movable against each other.

The carrier arm 12 supports a drill-head 26 arranged to slide in theaxial direction of the arm and to be secured thereto. For normaloperation the assembly comprising the elements 16, 14, 12 and 26 will bedisposed parallel to the floor of, for example, a tunnel in which theloader is working, and the drillhead will drill into a vertical wall notillustrated at right angles thereto. This is the position of theassembly illustrated in FIG. 1. If it is desired to drill the wall at alower elevation, but still at 90, the boom will be lowered and theassembly 16, 14 and 12 be swivelled relatively to the boom. If it isdesired to drill the vertical wall at an angle other than 90, it maysuffice to pivot the boom 2 only. Alternatively, in addition to pivotingthe boom the assembly 16, 14 and 12 may be swivelled relatively to theboom by swivelling the block 16 by means of the sprocket and chaintransmission, as previously indicated. Thus, the assembly can be set atany required inclination within the swivelling range of the block 16 anddrilling may take place at substantially any elevation of the verticalwall and also the floor may be drilled.

Valves not shown are provided for admitting hydraulic fluid to andexhausting it from the units 8 and and a hydraulic motor of thedrill-head 26 if the latter is hydraulically operated. These valves maybe mounted on a valve bank not shown in easy reach of the vehicleoperator and are connected by hydraulic ducts not shown to the units andthe motor.

The drill-head 26 in the embodiment illustrated is hydraulicallyoperable so that it can also be connected to the hydraulic system of thevehicle. Alternatively, the drilLhead 26 may be powered by othersuitable or available means, for example compressed air or electricpower.

If the vehicle is required to be used for its normal purpose, thedrilling-rig attachment may be stowed away by pivoting the boom 2 bymeans of the pistonand-cylinder unit 8 the unit 10, as alreadyindicated, having first been detached from the vehicle from itsillustrated position. The stowing position of the attachment on the sideof the vehicle is indicated in FIG. 1 by broken lines. The attachment isbrought into the latter position by pivoting the boom 2 in a verticalplane and rotating the whole of the attachment in a horizontal plane. Itis held in the stowing position by clamps or straps not illustrated.

Referring now to the embodiment illustrated in FIGS. 3 to 6, it will beseen that the attachment, although basically the same as thatillustrated in FIGS. 1 and 2, is arranged to be operated entirely byhydraulic actuating means. The actuation of the various hydraulicpiston-.and-cylinder units forming part of the attachment is controlledfrom a bank of manually operable hydraulic valves not illustrated ineasy reach of the vehicle's attendant.

The hydraulic piston-and-cylinder unit 8 is arranged to raise and lowerthe boom 2 in a vertical plane. The

lower end of the boom 2 is again pivotally mounted in the bracket 4which, as in the embodiment illustrated in FIGS. 1 and 2, is rotatableto a limited extent in a horizontal plane about the axis Y Y, shown inFIG. 3. A further hydraulic piston-and-cylinder unit 28 is provided foreffecting the limited rotary motion of the bracket 4 and thus of theboom 2. The cylinder of the unit 28 is attached to the vehicle while itspiston rod is pivotally attached to a crank arm 30 connected to thebracket 4 (see also FIG. 5). The crank arm 30 is connected to a tubularextension of the bracket 4 said extension extending through the bearing6 by means of a movable pin not illustrated. The pin is removed if it isrequired to rotate the boom 2 beyond the operating range of the unit 28,for example for the purpose of stowing away the attachment.

A support 32 of the drilling head carrier arm 12 is mounted in a block34 attached to the other, upper, end of the boom 2. It is mounted in theblock 34 so as to rotate about the axis C C which is normal to thelongitudinal axis of the arm 12 and which, in the position of the boomand the carrier arm illustrated in FIG. 3 is vertical permittingrotation of the support 32 and the arm 12 in a horizontal plane.However, it will be evident from the further description that the axisC- C can be moved out of its vertical position and hence the arm 12rotated in a plane other than horizontal even if, for ease ofdescription, the axis C C may be referred to as being vertical and therotary motion of the arm 12 as being in a horizontal plane. The block 34attached, as already stated, to the other end of the boom is mounted soas to be pivotable relatively to the boom 2 in a vertical plane aboutthe axis B B over an arc of substantially as in the embodimentillustrated in FIGS. 1 and 2. Thus, if the block 34 is pivoted out ofthe position illustrated, the axis C C will be tilted into a positionother than vertical, and any rotary motion of the support 32 and the arm12 will therefore be in a plane other than horizontal.

Rotation of the support 32 about the axis C C is effected by a pair ofhydraulic piston-and-cylinder units 36. The piston of each unit isjoined to a piston rod toothed to form a rack meshing with the teeth'ofa pinion 38 mounted fixedly in the block 34 and rotatably in .thesupport 32. When the piston-andcylinder units 36 are actuated, theirrespective piston rods will be moved out of or retracted into thecylinders causing the support 32 to rotate about the axis C C, that isto say relatively to the pinion 38, either in a clockwise or ananti-clockwise direction, depending upon which of the twopiston-and-cylinder units is pressurized.

The pivotal motion of the block 34 in a vertical plane is effected bymeans of an endless-drive transmission comprising a cross-head 40, ropesor chains 42 and 44, a driven wheel, or pulley, 46 fixed to the block34, a guide wheel, or pulley, 48, and a cross-head drivingpiston-and-cylinder unit 50. The rope 42 is attached at its one end tothe cross-head 40 and at its other end to the pulley 46. One end of therope 44 is also attached to the pulley. 46 while its other end afterpassing over the pulley 48 is attached to the cross-head 40. Thus, itwill be seen that the ropes 42 and 44 impart rotary motion to the pulley46 when the cross-head is moved along and parallel with the longitudinalaxis of the boom 2.

The boom is of profiled cross-section, for example rectangular, so as todefine a hollow space between two parallel side walls. Any othercross-sectional shape providing two spaced parallel walls, or edges, mabe used instead. The cross-head 40 is arranged to slide along the boom 2guided by its side walls when moved by the piston rod of the unit 50which is disposed in the hollow space of the boom 2. The cylinder of theunit 50 is pivotally attached by means of two pivot pins 52 to the sameside walls of the boom 2 that guide the crosshead 40. The piston rod ofthe unit 50 is connected to the cross-head 40 so that when the unit 50is actuated by pumping hydraulic fluid into the unit or exhausting ittherefrom, the cross-head 40 will slide along the boom 2 in the samedirection as the piston and piston rod of the unit 50 is caused to move.Since the crosshead 40 is connected through the ropes, or chains, 42 and44 to the pulley 46, its sliding motion will be transmitted to thelatter and to the block 34 so that motion of the cross-head 40 willcause the block 34 to pivot in the vertical plane.

The carrier-arm 12 supports a slide, or slidable base, 54 on which adrill-head 56 is rigidly mounted. Alternatively, the head 56 and thebase 54 may form an integral unit as the head illustrated in FIG. 1. Theslide 54 is arranged to be moved along the carrier-arm 12 by means of arope 58 attached thereto and trained over two rotatable pulleys 60 and62 one arranged at, or close to, each end of the carrier-arm 12. Therope 58, the ends of which are secured to two anchorages 59 one locatedat or close to each end of the arm 12 also passes over a pulley 64 of afurther cross-head 66 slidably attached to the carrier arm 12. Thecross-head 66 is arranged to be moved along the carrier-arm 12 by meansof a hydraulically operated carrier-arm pistonand-cylinder unit 68, thecylinder of which is joined by a pin 70 to the carrier-arm 12. The rope58 is trained over the pulley 60, 62 and 64 in such a fashion that itmultiplies the sliding motion of the slidable base 54 compared with thedisplacement of the piston in the unit 68 by a predetermined factorwhich in the embodiment illustrated is two so that if the total possibledisplacement of the piston is 3 feet 6 inches the slide together withthe drilling head 56 will be moved over a maximum distance of 7 feet.

The drill-head 56 includes a drill spindle arranged to be rotated by ahydraulic motor not illustrated. The drill insertable into thedrill-head is supported by a drill steady 72, mounted at the front endof the carrier arm 12 close to the pulley 62.

Thus, it will be seen that in contrast to the drilling rig illustratedin FIGS. 1 and 2, all rotary, pivotal or tilting motions of the rigillustrated in FIGS. 3 to 6 are affected hydraulically. However, it isto be understood that, except for the endless-drive transmission in theembodiment illustrated in FIGS. 1 and 2, all the other rotary, pivotalor tilting motions may also be produced by the hydraulicpiston-and-cylinder units described in connection with the secondembodiment.

As will be gathered from the preceding description of the twoembodiments, a drilling rig according to the invention is capable ofbeing permanently attached to a digger vehicle, particularly a vehiclearranged for side tipping. Its advantage is that it can stay attachedeven when it is required to use the vehicle for its primary purpose ofdigging and (side) tipping. In this instance, the rig merely requires tobe moved into its inoperative, or stowing, position on the vehicleitself. All that is needed to do this is to disconnect one end of one ofthe hydraulic piston-and-cylinder units actuating the boom or to takeout the removable pin referred to in connection with the crank-arm 30 inFIG. 3. This possibility of leaving the rig attached to the vehicle,thus permitting the latter to be used as a dual-purpose vehicle hasnever before been achieved. It has been necessary either to dismantlethe rig completely or to change from one type of vehicle, or applianceto another type. This has involved protracted interruption of work, notto mention the difficulty of moving one vehicle past the other in aconfined space, such as in mining or tunnelling. A rig according to theinvention whenmounted on a vehicle of the type referred to obviates thisdifficulty and reduces the interruption of work to a minimum. Thus, itwill reduce capital expenditure and working time and hence operatorswages.

What we claim is:

l. A drilling rig attachable to a bucket-digger vehicle equipped with ahydraulic actuating system, wherein the drilling rig comprises a boomone end of which is arranged to be pivotally attached to the vehiclewhile the other end supports a drilling-head carrier-arm tiltablymounted thereon and rotatable about an axis normal to the axis oftilting, wherein the boom is arranged to be pivoted in a vertical planeby at least one hydraulic piston-and-cylinder unit attachable to thevehicle and connectable to the hydraulic system, and an endless-drivetransmission extending substantially from the one end to the other endof the boom for tilting the carrier arm over an arc of substantially 2.The drilling rig of claim 1 wherein said endless drive transmissionincludes a drive wheel located at or close to the one end of the boom.

3. A drilling rig according to claim 2, wherein said drive wheel isarranged to be rotated by a worm and worm-wheel drive.

4. A drilling rig according to claim 3, wherein said worm ispower-driven.

5. A drilling rig according to claim 4, wherein the power is hydraulicpower.

6. drilling rig according to claim 2 wherein said drive wheel is asprocket connected by a chain to a driven sprocket fixed to a blocktiltably mounted at the other end of the boom and supporting thecarrier-arm.

7. A drilling rig according to claim I wherein the pivotal motion of theboom is effected by means of two hydraulic piston-and-cylinder units,one of which is detachably connected to the vehicle.

8. A drilling rig according to claim 7, including a means for pivotingthe boom in a horizontal plane.

9. A drilling rig according to claim 8, wherein the means for pivotingthe boom in a horizontal plane includes a hydraulic piston-and-cylinderunit.

10. A drilling rig according to claim I wherein said drilling-headcarrier-arm includes a support fixed to one end thereof, wherein thesupport is mounted in a block for rotary motion about an axis normal tothe longitudinal axis of said drilling-head carrier-arm, and wherein theblock is tiltably mounted on the other end of said boom.

11. A drilling rig according to claim 10, wherein the rotary motion ofthe block and said drilling-head carrier-arm is effected under hydraulicpower.

12. A drilling rig according to claim 11, wherein the hydraulic power isprovided by a pair of piston-andcylinder units.

13. A drilling rig according to claim 1 wherein the endless-drivetransmission comprises a cross-head arranged to slide along the boom, adriven wheel fastened to the block, a guide wheel mounted at or close tothe one end of the boom, a chain attached to the crosshead and thedriven wheel and trained over the guide wheel, and a piston-and-cylinderunit attached to the boom and arranged to impart sliding motion to thecross-head, the arrangement being such that in operation actuation ofthe driving piston-and-cylinder unit and the resulting sliding motion ofthe cross-head will tilt the block.

14. A drilling rig according to claim 13 wherein a drill-head isslidably mounted on said drilling-head carrier-arm.

15. A drilling rig according to claim 14, wherein hydraulically actuatedoperated means are provided to impart sliding motion to-the drill-head.

16. A drilling rig according to claim 15, wherein the actuating meanscomprise a further cross-head slidably mounted on the carrier-arm andarranged to be moved b a piston-and-cylinder unit mounted on the arm,two pulleys one rotatably mounted at or close to each end of the arm,and a rope fastened to the drill-head, trained over the pulleys andpassing around a pulley on the further cross-head, and wherein thepiston rod of the piston-and-cylinder unit is connected to the furthercross-head, the arrangement being such that in operating actuation ofthe piston-and-cylinder unit and the resulting motion of the furthercross-head will produce sliding motion of said drill-head.

17. A drilling rig according to claim 16, wherein the maximum slidingdistance of said drill-head is a multiple of the total displacement ofthe piston of the carrier-arm piston-and-cylinder unit, and wherein themultiplication is effected by training the rope over the pulley on thefurther cross-head.

18. A drilling-rig according to claim 17 wherein said drill-headcomprises a drill spindle arranged to be rotated by a hydraulic motor.

19. A drilling rig according to claim 1 wherein the bucket diggervehicle includes a bucket and means for tipping said bucket sideways.

1. A drilling rig attachable to a bucket-digger vehicle equipped with ahydraulic actuating system, wherein the drilling rig comprises a boomone end of which is arranged to be pivotally attached to the vehiclewhile the other end supports a drillinghead carrier-arm tiltably mountedthereon and rotatable about an axis normal to the axis of tilting,wherein the boom is arranged to be pivoted in a vertical plane by atleast one hydraulic piston-and-cylinder unit attachable to the vehicleand connectable to the hydraulic system, and an endless-drivetransmission extending substantially from the one end to the other endof the boom for tilting the carrier arm over an arc of substantially180*.
 2. The drilling rig of claim 1 wherein said endless drivetransmission includes a drive wheel located at or close to the one endof the boom.
 3. A drilling rig according to claim 2, wherein said drivewheel is arranged to be rotated by a worm anD worm-wheel drive.
 4. Adrilling rig according to claim 3, wherein said worm is power-driven. 5.A drilling rig according to claim 4, wherein the power is hydraulicpower.
 6. A drilling rig according to claim 2 wherein said drive wheelis a sprocket connected by a chain to a driven sprocket fixed to a blocktiltably mounted at the other end of the boom and supporting thecarrier-arm.
 7. A drilling rig according to claim 1 wherein the pivotalmotion of the boom is effected by means of two hydraulicpiston-and-cylinder units, one of which is detachably connected to thevehicle.
 8. A drilling rig according to claim 7, including a means forpivoting the boom in a horizontal plane.
 9. A drilling rig according toclaim 8, wherein the means for pivoting the boom in a horizontal planeincludes a hydraulic piston-and-cylinder unit.
 10. A drilling rigaccording to claim 1 wherein said drilling-head carrier-arm includes asupport fixed to one end thereof, wherein the support is mounted in ablock for rotary motion about an axis normal to the longitudinal axis ofsaid drilling-head carrier-arm, and wherein the block is tiltablymounted on the other end of said boom.
 11. A drilling rig according toclaim 10, wherein the rotary motion of the block and said drilling-headcarrier-arm is effected under hydraulic power.
 12. A drilling rigaccording to claim 11, wherein the hydraulic power is provided by a pairof piston-and-cylinder units.
 13. A drilling rig according to claim 1wherein the endless-drive transmission comprises a cross-head arrangedto slide along the boom, a driven wheel fastened to the block, a guidewheel mounted at or close to the one end of the boom, a chain attachedto the cross-head and the driven wheel and trained over the guide wheel,and a piston-and-cylinder unit attached to the boom and arranged toimpart sliding motion to the cross-head, the arrangement being such thatin operation actuation of the driving piston-and-cylinder unit and theresulting sliding motion of the cross-head will tilt the block.
 14. Adrilling rig according to claim 13 wherein a drill-head is slidablymounted on said drilling-head carrier-arm.
 15. A drilling rig accordingto claim 14, wherein hydraulically actuated operated means are providedto impart sliding motion to the drill-head.
 16. A drilling rig accordingto claim 15, wherein the actuating means comprise a further cross-headslidably mounted on the carrier-arm and arranged to be moved by apiston-and-cylinder unit mounted on the arm, two pulleys one rotatablymounted at or close to each end of the arm, and a rope fastened to thedrill-head, trained over the pulleys and passing around a pulley on thefurther cross-head, and wherein the piston rod of thepiston-and-cylinder unit is connected to the further cross-head, thearrangement being such that in operation actuation of thepiston-and-cylinder unit and the resulting motion of the furthercross-head will produce sliding motion of said drill-head.
 17. Adrilling rig according to claim 16, wherein the maximum sliding distanceof said drill-head is a multiple of the total displacement of the pistonof the carrier-arm piston-and-cylinder unit, and wherein themultiplication is effected by training the rope over the pulley on thefurther cross-head.
 18. A drilling-rig according to claim 17 whereinsaid drill-head comprises a drill spindle arranged to be rotated by ahydraulic motor.
 19. A drilling rig according to claim 1 wherein thebucket digger vehicle includes a bucket and means for tipping saidbucket sideways.